Liquid crystal displays have conventionally been mainly employed in digital watches, portable electronic computers and the like. However, liquid crystal displays have recently been utilized in the fields in which higher stability is required, such as displays in meters of automobiles, outdoor displays, etc.
The polarizing film used in the liquid crystal display system has a protective layer formed on at least one surface of a polarizer so that the life of the polarizer is prolonged.
Hitherto, various literature references have described that many plastic films, glass, etc., can be used as the protective layer, if such cellulose ester films are optically transparent. However, actually, only cellulose ester films and polyacrylic resin films have been practically used. The reasons for this is these resins not only have excellent optical transparency but also have a low degree of orientation and can be easily coated on the polarizer and hardened.
However, cellulose esters and polyacrylic resins practically used do not always have sufficient heat resistance, water resistance and dimentional stability as a polarizing film, and, therefore, there is a problem in that it is difficult to use these materials in display systems to be used under severe conditions such as displays in meters of automobiles, outdoor displays, etc. Accordingly, improvement in the protective layer has been desired.